Code of practice for general design details and preparatory work for damp-proofing and water-proofing of buildings

IS 3067: Scope & Key Specifications for Water-Proofing of Roofs

Scope (Clause 1.1):

• Covers design essentials for damp-proofing & water-proofing of new/existing buildings.
• Includes preparatory work: dewatering, surface prep before treatment.

Design Considerations (Clause 2.2):
Designer must consider:

• Roof shape (flat, sloping, curved)
• Roof type & finish
• Thermal insulation
• Roof projections (pipes, parapets)
• Drainage system
• Rainfall intensity
• Weight of water-proofing layers

Timber Roof Water-Proofing (Clause 6.2.2)

Key Figures (from IS 3067)

• Fig. 10: Waterproofing parapet wall without groove — includes bitumen filling & concrete fillet
• Fig. 11: Timber roof joint waterproofing with bitumen felt & caulking
• Fig. 12: Pipe penetration waterproofing with metal collar & bitumen caulking

Summary Diagram: Timber Roof Waterproofing Setup

flowchart LR
    A[Timber Board] --> B[Caulked Joint with Bitumen + Hemp]
    B --> C[Bitumen Felt Layer]
    C --> D[Wooden Angle Fillet 75x75 mm]
    D --> E[Vertical Wall]
    F[Pipe Penetration] --> G[Metal Flanged Collar 150 mm]
    G --> H[Bitumen + Hemp Caulking]

For detailed design, refer to IS 3067 clauses 1.1, 2.2, and 6.2.2 with figures

IS 3067: Key Info for Design & Preparatory Work for Damp-Proofing & Water-Proofing

Necessary Information for Design (Clause 2.1)

For basement damp-proofing, the designer must gather:

• Highest anticipated water level (dry & rainy seasons)
• Water table fluctuations and rate of change
• Maximum water pressure on structure
• Chemical & bacteriological composition of subsoil water
• Foundation/basement drawings and design features
• Construction schedule for coordination

Preparatory Work & Scheduling (Clause 5.1)

Coordinate operations to avoid delays and equipment conflicts:

• Excavation completion dates
• Readiness of base, walls, scaffolding, pumps for damp-proofing start
• Progress milestones for damp-proofing to allow structural work continuation

Surface Preparation (Clause 6)

• Clean, dry, and sound surfaces free of loose material
• Remove standing water before application
• Ensure proper curing and drying time before waterproofing

Typical Water Pressure Calculation:

[ P = \gamma_w \times h ]

• (P) = water pressure (kN/m²)
• (\gamma_w) = unit weight of water (≈ 9.81 kN/m³)
• (h) = height of water column (m)

flowchart TD
    A[Site Survey] --> B[Determine Water Table & Pressure]
    B --> C[Assess Chemical Composition]
    C --> D[Prepare Drawings & Schedule]
    D --> E[Excavation & Surface Prep]
    E --> F[Damp-Proofing Application]
    F --> G[Structural Work Continuation]

This ensures effective, durable damp-proofing and waterproofing per IS 3067.

IS 3067: Design Considerations for Waterproofing Roofs

Key Factors (Clause 2.2)

• Roof shape: flat, sloping, curved
• Roof type & finish required
• Thermal insulation
• Projections (pipes, chimneys)
• Drainage arrangement
• Rainfall intensity
• Total weight of waterproofing

Design Points (Clause 3.2)

• Expansion joints: Use non-absorbent, compressible, watertight sealants.
• Drain openings: Size and number per IS 2527:1984 Table 3.
• Ease of waterproofing application: Design openings accordingly.
• Parapet walls: Provide grooves ≥150 mm above roof for waterproofing insertion.
• Ornamental parapets: Waterproofing tucked in solid parts.
• Lime terracing junction: Leave cavity for lime concrete flashing (IS 3036:1980).

Timber Roof Waterproofing (Clause 6.2.2)

• Caulk gaps in timber boards with hemp/hessian impregnated with bitumen.
• Nail boards adequately to prevent curling.
• Chamfer or round sharp edges.
• Provide 75×75 mm wooden angle fillets at roof-wall junctions.
• Use metal flanged collars (150 mm wide flange) around pipes penetrating roofs.

Table: Drain Opening Sizes (per IS 2527:1984 - Table 3 excerpt)

Summary Diagram: Waterproofing at Timber Roof Pipe Penetration

flowchart TB
    A[Timber Boarding] --> B[Bitumen Felt]
    B --> C[Bitumen + Hemp Caulking]
    C --> D[Metal Flanged Collar (150 mm flange)]
    D --> E[Pipe Projection]

References:

• IS 3067: Waterproofing Code
• IS 2527:1984: Roof Drainage
• IS 3036:1980: Lime Concrete Flashing

Planning in Relation to Subsoil Drainage (IS 3067)

Key Points & Specifications:

• Dewatering during damp-proofing:

  • Keep subsoil water level below work level by pumping (Fig. 1-4).
  • Use well-point system or sump pumping in basements with persistent water.
  • For limited space, provide alternate pumping and shoring (Fig. 4).

• Damp-proofing details:

  • Mortar bed must be level and smooth to avoid damage.
  • Provide a 75 mm radius cement mortar fillet (1:4) at horizontal-vertical junctions (Fig. 5).
  • DPC course (12 mm thick cement mortar 1:4 or cement concrete 1:2:4) with waterproofing compound (IS 2645) below brick edges.
  • Extend DPC vertically on inner basement walls.

• Timing:

  • Carry out damp-proofing in dry season when water table is lowest (Clause 2.1).
  • Drain standing water before starting work.

Typical DPC Thickness & Mix (Clause 6.1.1 & Fig. 5B)

Dewatering Arrangement (Summary)

flowchart LR
    SubsoilWater -->|Pumping| Sump
    Sump -->|Discharge| Pump
    Pump -->|Water Out| DrainageSystem
    DrainageSystem -->|Prevents Backflow| Bund

Additional Notes:

• Design drainage openings per IS 2527-1984 Table 3 for roof drainage (Clause 3.2).
• Use tar felt or similar covers on land drains to protect waterproofing (Fig. 3).
• Consider chemical and bacteriological effects of subsoil water (Clause 2.1e).

This ensures effective damp-proofing and structural durability against subsoil water ingress.

IS 3067: Time Schedule for Basement & Damp-proofing Work

Key Points from Clause 5.1:

• Time schedule must coordinate all operations to avoid interference.
• Include:
  • Excavation completion date
  • Readiness of base, walls, scaffolding, pumping for damp-proofing start
  • Progress milestones for damp-proofing to allow structural work start

General Recommendations:

• Efficient site and underground drainage must be maintained throughout.
• Dewatering must keep water level below work level (use pumps, well-point system).
• For existing basements, damp-proofing should be done in dry season after draining water.

Suggested Time Schedule Outline (Example):

Dewatering Arrangement (Fig. 1-4 in IS 3067):

• Use well-point system or floor pump for subsoil water.
• Shoring required if space is limited.

Summary Diagram:

gantt
    title Basement Construction & Damp-proofing Schedule
    dateFormat  YYYY-MM-DD
    section Excavation
    Excavation Complete          :done, 2024-06-01, 10d
    section Preparation
    Base & Wall Prep             :active, after Excavation, 7d
    section Damp-proofing
    Start Damp-proofing          :after Preparation, 14d
    Damp-proofing Progress Check :milestone, after 7d of Damp-proofing
    section Structural Work
    Structural Walls & Floor     :after Damp-proofing, 14d

Note: Always coordinate schedule with contractors for pumps and equipment use to optimize cost and avoid delays.

IS 3067: Key Points on Surface Preparation & Damp-Proofing of Basements and Roofs

1. Preparation of Surface (Clause 6.1.2.1)

• Vertical walls: Roughen by hacking or plaster finish for good grip.
• Floor: Clean and level as much as possible.
• Fillet: Provide a 75 mm radius cement mortar fillet at junctions of horizontal & vertical surfaces and between adjacent walls.

2. General Recommendations for Damp-Proofing (Clauses 2.1, 5.1)

• Schedule damp-proofing when subsoil water is lowest (dry season).
• Designer must know:
  • Highest water level & water table during rainy season.
  • Rate of water table change.
  • Maximum water pressure.
  • Chemical/bacteriological effects of subsoil water.
  • Foundation/basement drawings.
  • Construction schedule to avoid work interference.
• Coordinate excavation, base/wall readiness, scaffolding, pumping, and damp-proofing progress.

3. Typical Damp-Proofing Layers (Fig. 5 & 6)

4. Sequence of Work (Fig. 6)

graph LR
A[Brick flat or Cement concrete (1:3)] --> B[Horizontal damp-proofing]
B --> C[Vertical damp-proofing on outside faces]
C --> D[Structural walls and floor]
D --> E[Outer protective walls]

Summary:

• Roughen surfaces for bonding.
• Provide fillets at junctions.
• Schedule damp-proofing during dry season with full site data.
• Follow layered construction with specified mortar/concrete mixes.
• Coordinate all activities to avoid delays.

IS 3067: Damp-Proofing of Basements — Key Points & Specifications

1. Timing & Basic Info (Clause 2.1)

• Damp-proofing should be done when subsoil water level is lowest (dry season).
• Designer must know:
  • Highest water level & rainy season water table
  • Rate of water table change
  • Max water pressure
  • Chemical/bacteriological effects of subsoil water
  • Basement/foundation drawings
  • Construction schedule

2. Damp-Proofing Treatment (Clause 6.1 & 6.1.2.1)

• Surface Preparation:

  • Roughen vertical walls by hacking/plaster for grip.
  • Clean and level floor.
  • Provide cement mortar fillet (1:4), 75 mm radius at junctions of horizontal & vertical faces.

• Materials:

  • DPC: Cement mortar 1:4 or cement concrete 1:2:4, 12 mm thick with waterproofing compound (IS 2645).
  • Use integral cement waterproofing compounds.
  • Floor filling: Lime or cement concrete.

• Coverage:

  • DPC covers full wall thickness (excluding rendering).
  • Extend DPC vertically inside basement wall edges.

3. Typical Layering (Fig. 5 & 6 summary)

4. Dewatering Arrangements (Figs. 1-4)

• Use bunds to prevent backflow.
• Land drains with loose ballast and tar-felt cover.
• Alternate pumps for continuous dewatering.

Summary Mermaid Diagram: Basement Damp-Proofing Layers

graph TD
    A[Lean Cement Concrete Base Slab]
   

IS 3067: Above Ground Level - Damp Proofing Key Points

Clause 6.1.1: Above Ground Level Moisture Control

• Moisture rises by capillary action above ground level.
• Damp-proofing is critical in floors and walls to prevent moisture ingress.

Important Specifications for Damp Proofing (Fig. 5A & 5B)

• Mortar bed must be level and free from projections to protect damp-proofing.
• At junction of horizontal & vertical surfaces, provide a cement mortar fillet (1:4) with 75 mm radius.
• Damp-proofing should cover full wall thickness (excluding rendering) without setback.
• For basement walls, provide a DPC course of cement mortar (1:4) or cement concrete (1:2:4), 12 mm thick, with waterproofing compound per IS 2645-1975.
• DPC may extend vertically on inner brick edges.
• Floor finish should be continuous up to the superstructure inner face.

Typical Layers (from Fig. 5):

• 75 mm lean cement concrete (smooth finished)
• Cement mortar fillet (75 mm radius)
• Damp proof treatment layer
• Lime or cement concrete base

Summary Table: Damp Proofing Thickness & Materials

flowchart TB
    A[Ground Level] --> B[Lean Cement Concrete (75 mm)]
    B --> C[Cement Mortar Fillet (75 mm radius)]
    C --> D[Damp Proof Treatment Layer]
    D --> E[Wall Full Thickness with DPC]
    E --> F[Floor Finish up to Superstructure]

Note: Proper dewatering and drainage (see Figs. 1-4) are essential before laying damp-proofing to avoid water pressure buildup.

IS 3067 - Below Ground Level Damp Proofing & Dewatering Key Points

1. Dewatering Arrangements (Clause 4.1 & Fig. 1-4)

• Continuous site drainage during damp-proofing application is essential.
• Use pumps, well-point systems, or land drains to keep water below work level.
• For limited space, use alternate pumping arrangements and shoring (Fig. 4).
• Land drains: loose ballast-filled trench with tar-felt cover (Fig. 3).

2. Damp-Proofing Treatment (Clause 6.1.2)

• Base slab: Lean cement concrete, smooth finish, strong enough for construction traffic.
• Slab projects ≥ 250 mm beyond structural walls (Fig. 6).
• Vertical & horizontal DPT continuity: Provide 75 mm radius cement mortar fillet at junctions.
• Vertical DPT applied on smooth/roughened wall exterior or internal face of protective wall (Fig. 7).
• Protective walls: Outer wall (300-400 mm thick), inner wall with 100 mm grout space.

3. Specifications for Basement Walls (Clause 6.1.2.1)

• Mortar bed leveled, free of projections.
• DPC course: Cement mortar 1:4 or cement concrete 1:2:4, 12 mm thick with waterproofing compound (IS 2645).
• DPC covers full wall thickness, flush with wall face.

Summary Table

flowchart TD
    A[Excavation] --> B[Lean

Internal Tanking of Existing Building (IS 3067 - Clauses 6.1.2.1 & 4.1)

Key Specifications:

• Wall Preparation: Vertical walls must be roughened by hacking or rough plaster finish for proper bonding.
• Floor Preparation: Clean and level the floor as much as possible.
• Fillet: Provide a cement mortar fillet of 75 mm radius at junctions of horizontal and vertical surfaces.

Damp-proofing Application:

• Apply integral cement waterproofing compounds in cement mortar or concrete.
• For existing basements, internal tanking must be done when the basement is dry or water is pumped out.
• If subsoil water percolates, use well-point dewatering or pump from the floor with waterproof plug after treatment.

Typical Cement Mortar Mix for Damp Proof Course (DPC)

• DPC Thickness: 12 mm with waterproofing compound.
• Fillet Radius: 75 mm at wall-floor junctions.

Sequence for Internal Tanking Work

flowchart TD
    A[Surface Preparation] --> B[Apply Cement Mortar Fillet (75 mm radius)]
    B --> C[Apply Integral Cement Waterproofing Compound]
    C --> D[Allow to Set]
    D --> E[Protective Layer / Finishing]

Important Notes:

• Internal tanking is preferred for existing buildings where external excavation is not feasible.
• Work should be done in dry season or after dewatering.
• Continuous treatment on walls and floors is essential for effective waterproofing.

For detailed design of reinforcement and structural considerations, refer to IS 456 and IS 3370 as applicable.

External Tanking of New Buildings (IS 3067: Clause 6.1.2.2)

Key Specifications:

• Base Slab:

  • Lean cement concrete slab on excavation floor.
  • Smooth surface finish.
  • Strength to withstand construction traffic.
  • Extends ≥ 250 mm beyond outer faces of structural walls.

• Structural Walls:

  • Exterior surface smooth or roughened as required.
  • Vertical damp-proofing continuous with horizontal damp-proofing.
  • Provide a 75 mm radius cement concrete fillet at junctions.

• Protective Walls (When space limited):

  • Outer protective wall: 300-400 mm thick (depending on depth and earth pressure).
  • Inner protective wall: at least one brick thick.
  • Damp-proofing applied on internal face of outer wall.
  • 100 mm gap between damp-proofing and inner protective wall, later cement-grouted.
  • Fillet of 75 mm radius at base slab and protective wall junction.

Sequence of Work (Fig. 7):

Fillet Detail:

• Radius: 75 mm
• Material: Cement concrete mortar

Summary Table of Thicknesses:

flowchart TD
    A[Excavation] --> B[Base slab of lean cement concrete]
    B --> C[Horizontal damp-proofing]
    C --> D[Outer protective wall (300-400 mm)]
    D --> E[Vertical damp-proofing on outer wall]
    E --> F[Inner protective wall (≥ 1 brick thick)]
    F --> G[RCC Structural wall]
    B -.

IS 3067 - Gunite Work & Waterproofing Key Points

Gunite Work (Clause 6.1.3)

• Surface preparation: Remove loose material; clean with compressed air and water.
• Concrete surfaces: Roughen by light chipping.
• Masonry joints: Rake out to 12 mm depth for good bonding.
• Reinforced gunite: Use dowels on underground structures under subsoil water pressure to prevent blowing off.

Waterproofing of Roofs (Clause 6.2 & 6.2.1)

• Crack treatment: Cut well-defined cracks to 'V' section; fill with cement-sand slurry or bituminous caulking (IS:1580-1969).
• Surface cleaning: Remove fungus, moss, dust by wire brushing.
• Surface finish: Rough finish for lime concrete or gunite bonding.
• Drain outlets: Widen masonry drain mouths 2.5× pipe diameter; round with cement mortar.
• Pipe penetrations: Provide cement concrete angle fillet around pipes; extend waterproofing over fillet.
• Parapet walls:

  • 450 mm: Provide groove 75 mm wide × 65 mm deep, 150 mm above roof level for tucking waterproofing.

  • ≤450 mm: Waterproofing carried over top without groove.
• Fillets: 75 mm radius fillet at roof-parapet junction for smooth water flow.

Typical Dimensions Summary

Diagram: Pipe Penetration Waterproofing

flowchart LR
    A[Pipe through Roof] --> B[Cement Concrete Angle Fillet]
    B --> C[Waterproofing Layer Over Fillet]
    C --> D[Roof Surface]

Note: Always ensure structural soundness to prevent cracking and maintain continuous damp-proofing without joints where possible

IS 3067: Key Points on Water-Proofing of Roofs

1. Design Factors (Clause 2.2)

Consider these before waterproofing design:

• Roof shape: flat, sloping, curved
• Roof type and finish
• Thermal insulation
• Projections & drainage arrangement
• Rainfall intensity
• Total weight of waterproofing layer

2. Surface Preparation & Treatment (Clause 6.2 & 6.2.1)

• Crack repair: Cut V-shaped, fill with cement-sand slurry or bituminous caulk (IS 1580).
• Clean roof surface (remove moss, dust).
• Rough finish for lime concrete bonding.
• Drain outlets: widen masonry drains 2.5× pipe diameter; grooves for cast iron outlets.
• Pipe penetrations: Use cement concrete angle fillet (75 mm radius fillet at roof-parapet junction).
• Parapet walls >450 mm: Provide groove 75 mm wide × 65 mm deep, 150 mm above roof for tucking.
• Parapet ≤450 mm: Waterproofing carried over top without groove.

3. Drainage (Clause 3.2)

• Expansion joints sealed with non-absorbent, compressible sealants.
• Drain openings per IS 2527 Table 3.
• Provide grooves in parapet walls for waterproofing tuck-in.
• Lime terracing junctions require cavity for lime concrete flashing (IS 3036).

Typical Dimensions for Groove & Fillet:

Diagram: Pipe Penetration Waterproofing

flowchart TB
    A[Roof Surface] --> B[Concrete Angle Fillet]
    B --> C[Waterproofing Layer]
    C --> D[Pipe]
    style B fill:#f9f,stroke:#333,stroke-width:2px

References:

• IS 1580: Bituminous compounds for waterproofing
• IS 2527: Rainwater gutters and downpipes
• IS 3036: Lime concrete for waterproof roof finish

IS 3067: Concrete and Masonry Roofs - Key Specifications & Details

1. Crack Treatment (Clause 6.2.1a)

• Well-defined cracks (not hairline) are cut to a 'V' section, cleaned, and filled flush with:
  • Cement-sand slurry, or
  • Cold-applied bituminous caulking compound (IS:1580-1969)
• Surface regraded and cured before waterproofing.

2. Surface Preparation (6.2.1b,c,d)

• Clean roof, parapets, gutters from fungus, moss, dust (wire brushing).
• Lime concrete treatment requires rough finish for bonding.
• Gunite treatment per Clause 6.1.3.

3. Drainage (6.2.1e,f,n,p)

• Drain mouths widened 2.5× drain diameter, rounded with cement mortar.
• Cast iron drains: groove cut around for waterproofing tuck-in.
• Outlets at low dividing walls (<300 mm) fully open, smooth, rounded.

4. Pipes Through Roof (6.2.1g)

• Cement concrete angle fillet around pipe.
• Waterproofing carried over fillet.

5. Parapet Walls (6.2.1h,j,m)

6. Typical Fillet & Groove Details

• Fillet radius: 75 mm at parapet-roof junction.
• Groove horizontal face shaped with cement mortar.

7. Timber Roof Waterproofing (6.2.2)

• Joints caulked with hemp/hessian impregnated with bitumen.
• Boards nailed to prevent curling.
• Wooden angle fillet 75×75 mm at wall junction.
• Pipes surrounded by metal flanged collar (150 mm flange width).

Diagram: Pipe Waterproofing on Concrete Roof (Fig. 8)

flowchart TB
    A[Roof Surface] --> B[Concrete Angle

IS 3067 - Timber Roofs: Key Specifications & Details (Clause 6.2.2)

Waterproofing Treatment for Timber Roofs:

• Board Joints:

  • Non-tongued/grooved boards: Joints must be caulked with hemp/hessian fiber impregnated with bitumen or suitable filler.
  • Tongued/grooved boards: Caulking still necessary if gaps exist.
  • All joints must be adequately nailed to prevent curling.

• Edge Treatment:

  • Sharp edges/corners must be chamfered or rounded before waterproofing.
  • Provide a wooden angle fillet 75 × 75 mm where timber roof meets vertical wall to avoid sharp corners.
  • For timber walls, use wooden moulding to seal top edge of bitumen felt at 150 mm height from roof-wall junction.

• Pipe Penetrations:

  • Use a metal flanged collar with a 150 mm wide flange around pipes passing through the roof.
  • Collar must be caulked with bitumen and hemp and covered with bitumen felt collar (see Fig. 12).

Typical Dimensions & Details

Summary Diagram (Waterproofing Treatment of Timber Roof)

flowchart TB
    A[Timber Boards] --> B[Caulk joints with bitumen-impregnated fiber]
    B --> C[Nail joints adequately]
    C --> D[Chamfer/Round sharp edges]
    D --> E[Apply bitumen felt layers]
    E --> F[Wooden angle fillet (75x75 mm) at wall junction]
    F --> G[Seal top edge of bitumen felt with wooden moulding at 150 mm height]
    H[Pipe penetration] --> I[Metal flanged collar (150 mm flange)]
    I --> J[Caulk collar with bitumen & hemp]
    J --> K[Cover with bitumen felt collar]

References:

• IS 3067: Clause 6.2.2 and Figures 10, 11, 12